Drying and grading plants for granular water-containing materials



March 19, 1929. HQMGMANN ET AL 1,705,617

DRYING AND GRADING PLANTS FOR GRANULAR WATER CONTAINING MATERIALS Filed June 2, 1926 mvanrons:

Patented aw, 1929.

UNITED STATES;

v 1,705,611 PATENT OFFICE.

; LUDWIG nomemann, or ran 'roLz'Ann "FRIEDRICH BARTLING, or nunrcn.

' GERMANY.

15mm Ann GRADING rLANrs ron. enANUnAit .wArEn-cqmmmme MATERIALS.

Application filed June 2, 1936, Serial 1&05113387, and in Germany June 3, 1925.

This invention relates generally to well known oven plants in which granular watercontaining material, such as for example moist coal, is dried bycontinuous working.

5 To this end use may be made for example of the known revolving ring ovens 1n which a ring continuously revolving within a heated mufiie is charged with av th n layer of the material to a be dried thus carry ng it n through the oven chamber after whichfhe material. is carried out again-1n-var1ous ways. If the material is taken out in the usual manner simply by being wlped oil the carrier it is received in the form of a mixture of various grain sizes and mostly also in a not quite dry condition. I

' The object of the invention is to. enable the material to be obtained in absolutely dry condition and at the sanfe tlme graded g according todifferent grain sizes while in 'addition the utilization of the heat employed is improved andthe out put enlarged. According to this invention provislon is.

made .of means, inco-operation with the 5 constantly operating drying oven, for en- .richingo a preliminarily heated air on gas current at the delivery point of the oven -with the granular material and ,thereafter conveying it through a series of gradingv and dust clearing devices inwhichv operation, -while the drying of the material by the heat of the suction air continues, the

coarsest down to the finest dust particles are consecutively separated.

' In the ordinary continually acting drying ovens the heating gases pass away mm the oven with a"material remnant of useful P heat. According to this invention this heat remnant is utilized fof the preliminary 'heating,of the suction air which then'passes to the drying material along its whole travel through-the grading and dust removing device, taking up the moisture withdrawn -the'refrom. I 1 i 'To thisend according to this invention, use is made in front of the-suction point of a heat exchanging device utilizing as heat liberating means the oven gases and as heat absorbing means the suction air.

' ,In order to attain a gradingaccording tograin sizes the suction conduit according to this invention is provided in the rear of the suction point with consecutivepockets into which the various grain sizes of the material Qonnected to the drying oven A,

are caused successively to drop commencing, of course, with the coarsest grain sizes.

Following this grading device are, ac; cording to this invention, preferably number of dust removers due to. the fact that at that stage the suction air still carries with it a large amount of dust-like material. In this wayit is possible to obtain the drying material carried along almost entirely and properly graded according to sizes so that at the end of the suction con'- duit the suction lair passes out almost entirely freev from dust.

. A constructional form of the invention is by way of example diagrammatically il-.

lustratedin the annexed drawing. The installation comprises a dryin oven A which in the instance shown is a simple revolving ring oven with a revolving ring rotatifig in a muflie on to which ring the material is charged in the form of a thin'layer while the oven chamber is directly or indirectly heated so that at the end of the." rotation the materialis discharged in as dry a condition as possible. accord- '80 mg to this invention, is ag air conduit B through which air or gas is continually drawn in the direction of the arrow 7 by the action of, a pump F. The air first enters,

ate, a heat exchanging device a of any appropriate' construction and while passing through the latter from a to 6 acts as a heat absorbing means.

The means giving off heat are the combustion gases of the oven whichrare conveyed therethrough from d toe. From I) the suction air travels to the delivery point D of the oven and at this point it is interrupted by a jet-like device with the aid of' which the suction air has mingled therewith the granular material supported on the ring 1 of the oven. The dust carrying suction air. now passes to the grading device E which is composed of anumber of pockets 6*, e", e adapted to'receive'successively the coarsest grain sizes. These grain sizes may then'be discharged by the manipulation of appropriate chutes or slides. 'The heated air acts over the whole course suction air through the conduit B exerting a drying 'efi'ect (in-the drying material carried thereby.

In the consecutive grading and dust removing devices the granular and dash like material is gradually withdrawn from the air and in exchange it becomes charged with the moisture from the material. The suction air freed from the coarsest anular constituents then travels due to t e action of the pump into a dust remover G of any desired vconstruction in which the dust particles are to a large extent recipitated,collectin in the hopper shaped ottom g from which hey with a drying oven; of a conduit connected to said oven atits delivery point, a heatexchanging device connected to said oven to receive oven gases therefrom for prelimi narily heating suction air passing through said device to said delivery point, and means for creating a current of said-suctlon air past-said delivery point and into said conduit to convey all of the material-in said oven into said conduit wherein said material is dried by said current.

,2. In an apparatus for drying ranular water-containing materials, the com ination with a dryingoven; of a conduit connected to said oven at its delivery point, a heatexchanging device connected to said oven to receive oven gases therefrom for preliminarily heating suction air passing throu h said device to said delivery point, means or creating in addition to'the combustion gases in said oven, a current of said suction 'air oven" into said conduit wherein said material is dried by said current, and a dust-removfecting a removal of dust from said suction air. q

f In testimony whereof we have signed our names to this specification. I

LUDWIG Homema- FRIEDRICH BARTLING.

- past said delivery point and into said con j duitto convey all of the material in said' ing device connected to said conduit for ef- 

